3 Answers
3

You can't do this directly from Excel; you need to use an external application:

Select the chart, and then copy it to the clipboard (Ctrl-C).

Open a picture editor that supports saving to PNG.

Do a paste in the picture editor (when copying the chart from Excel
2010, it is recognized as a valid picture on the clipboard). The best will be to paste as new image if the picture editor supports that.

If you're working within the Office environment you don't need any other software, all you need to do is select & copy your chart then choose the Paste Special option. One of those paste options is PNG. The others include:

PNG

JPEG

GIF

EMF

BMP

Microsoft Office Drawing Object

If you need to export outside of the Office environment, then you can use Office Picture Manager. Just paste your chart inside your My Pictures folder (or whereever is most convenient). My charts paste as PNG by default, but if yours don't, you can choose your image and File>Export and choose your file type, inlcuding PNG, from the list.